Glossary of wildfire terms

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The following is a glossary of wildfire terms. Except where noted, terms are taken from a 1998 Fireline Handbook transcribed for a Conflict 21 counter-terrorism studies website by the Air National Guard.[1]

Separate glossaries for firefighting terms and firefighting equipment are also available.


1hr, 10hr, 100hr, 1000hr fuels
Refers to the time lag classes of Dead fuels classified by size: 1hr = 0 to 0.25 inch diameter. 10hr 0.25 to 1, 100hr 1 to 3, 1000hr 3 to 8.


Aerial canopy
Fuel type consisting of trees having few low branches, making it less susceptible to ignition by low-intensity fires.
Aerial firefighting (or air attack)
Use of aircraft in support of ground resources to combat wildfires, often most effective in initial attack in light fuels.
Air drop
Delivery of supplies or retardant from the air. Supplies can be dropped by parachute. Retardant is released in a single drop or one or more trails, the size of which is determined by the wind and the volume, speed and altitude of the airtanker (usually no less than 200 feet above the drop zone).
Air operations
Group tasked with coordinating aerial-based observation, supply, rescue and suppression at a wildfire.
Air tactical group supervisor or air attack
Coordinates air resources for attack of a fire
Fixed-wing aircraft certified by the FAA as being capable of transporting and delivering 600 to 3,0000 gallons of water or other liquid or powder fire retardants. Formerly referred to as borate bombers before borate-based retardants became less desirable. Often accompanied by a spotter plane.
Anchor point
An advantageous location, usually a barrier to fire spread, from which to start constructing a fireline. The anchor point is used to minimize the chance of being flanked (or outflanked) by the fire while the line is being constructed.


Precautionary fire set downwind of main fire for controlled fuel clearing by backing it into the main fire, similar to burnout, below, which occurs adjacent to control line.
A fire set along the inner edge of a fireline to consume the fuel in the path of a wildfire and to change the direction or force of the fire’s convection column.
Bambi bucket
Collapsible bucket for lifting and moving water and other fire retardant with a helicopter.
Any obstruction to the spread of fire. Typically an area or strip devoid of combustible fuel.
(1) staging or command center location for fire operations; (2) starting location of a fire; (3) base camp: location for eating, sleeping, etc., near staging or command center.
Soil heaped on the downhill side of a traversing fireline below a fire, to trap rolling firebrands.
A condition where no combustible fuels remain between the fireline and the main fire.
A sudden increase in fireline intensity or rate of spread of a fire sufficient to preclude direct control or to upset existing suppression plans. Often accompanied by violent convection and may have other characteristics of a firestorm.
Boise Interagency Fire Center (BIFC)
The former name of the National Interagency Fire Center (see below);
Bone yard
An area scraped to mineral soil for safe handling of smoldering materials; also, a systematic mop-up of smoldering materials by scraping off embers and placing materials into the bone yard area.[2]
Booster hose, booster pump, booster reel
A small solid hose on a reel connected to a small pump fitted to a water tank on a vehicle. Booster pump also refers to a pump in a relay series for pumping uphill beyond the lift of the previous pump.
Brush blade
Rake attachment for cutting or ripping brush and roots out of a fireline.
Brush hook
Cutting tool used to clear brush, longer than a machete, usually with a heavy, solid, curved blade bolted to the end of an arm's-length handle.
Brush truck
Small fire truck outfitted for wildland fire. Also called a type-six engine.
Bump up
To move to another location. Can refer to anything from moving to another location on a fireline, to an entire crew moving to another fire. Bump back means to return to a previous location. In the "bump" system of fireline construction, each firefighter works on a small piece of fireline with his or her tool until a completed portion of line is encountered. Then the call to bump up is heard, and everyone ahead of the caller skips ahead one or more positions, leaving the unfinished fireline for those coming up behind.
Burning index
A relative measure of fire-control difficulty; doubling the index means twice the effort may be needed to control the fire.
Burn out
Setting fire inside a control line to consume fuel between the edge of the fire and the control line.
Burning period
The part of each 24-hour period when fires spread most rapidly; typically from 10:00 AM to sundown.
A bushfire is a wildfire that occurs in the forests, scrubs, woodlands or grasslands of Australia or New Zealand.


A standing tree with a broken top which often continues to burn after the main firefront has passed. Candles usually send up a fountain of sparks and burning embers which may travel some distance and be of concern if near the unburnt side of a control line.
Closed area
An area in which specified activities or entry are temporarily restricted to reduce the risk of human-caused fires.
Legal restrictions of specified activities such as smoking, camping, and entry that might cause fires in a given area.
Cold trailing
A method of controlling a partly dead fire edge by carefully inspecting and feeling with the hand for heat to detect any fire, and lining any live edge.
Two or more individual incidents located in the same general area which are assigned to a single incident commander or unified command.
Confine a fire
The least aggressive wildfire suppression strategy which can be expected to keep the fire within established boundaries of constructed firelines under prevailing conditions.
Contain a fire
A moderately aggressive wildfire suppression strategy which can be expected to keep the fire within established boundaries of constructed firelines under prevailing conditions.
Control line
An inclusive term for all constructed or natural barriers and treated (retardant) fire edges used to control a fire.
Controlled burn
See prescribed burn (Rx burn)
Coyote tactics
A progressive line construction duty involving primarily hotshots and jumpers who build firelines until the end of the operation and then bed down where ever they end up, with no sleeping bag.
Creeping fire
Fire burning with a low flame and spreading slowly
Crown fire
A fire that advances from top to top of trees or shrubs more or less independently of a surface fire. Crown fires are sometimes classed as running or dependent to distinguish the degree of independence from the surface fire.
Crown out
See torching


Dead man zone
Unburnt areas around the edges of a brush fire.
Dead out
When a fire is completely out, with no smoldering or burning areas. (This is different from contained)
Demobilization, or, a crew being removed from working a fire.
Direct attack
Any treatment applied directly to burning fuel, such as wetting, smothering, or chemically quenching the fire or by physically separating the burning from the unburned fuel.
Dozer line
Fireline constructed by the front blade of a bulldozer or any tracked vehicle with a front-mounted blade used for exposing mineral soil. Also catline
Using a suction pump to lift water from below the pump, using a semi-rigid suction hose, typically to fill a portable reservoir that has other suction pumps (to relay) or siphon hoses running downhill to their nozzles.
Drip torch
A hand-carried fire-starting device filled with flammable liquid that is poured across a flaming wick, dropping flaming liquid onto the fuels to be burned.
Layer of decaying forest litter consisting of organics such as needles, leaves, plant and tree materials covering the mineral soil. Duff can smolder for days after a fire. Extinguishing smoldering duff is key to successful mop-up operations.


Any ground vehicle providing specified levels of pumping, water, and hose capacity but with less than the specified level of personnel.
Engine crew
A number of personnel trained to respond to incidents using an engine. Typically much smaller than a hand crew.
Escape fire
An intentionally started fire, ignited by a fire crew, usually in a grassland environment, to escape a dangerous situation.
Escaped fire
A fire, which has exceeded or is expected to exceed initial attack capabilities or prescription.
Extended attack
Situation in which a fire cannot be controlled by initial attack resources within a reasonable period of time. Committing additional resources within 24 hours after commencing suppression action will usually control the fire.


Fire behavior
The manner in which a fire reacts to the influences of fuel, weather, and topography.
Fire blindness
Failure to recognize the prominent ecological and evolutionary role of fire in fire-prone ecosystems[3].
Fire camp
Temporary camp established at large fires to provide food, rest, and other necessities to fire crews.
Fire cycle
Fire danger
Fire ecology
A scientific discipline/branch of ecology concerned with interactions between abiotic and biotic components of ecosystems, the role of fire as an ecosystem process, and its ecological effects on vegetation, plant communities, soils, wildlife, and landscapes.
Fire edge
The boundary of a fire at a given moment.
Fire fighting foam
The aerated solution created by forcing air into, or entraining air in water containing a foam concentrate by means of suitably designed equipment or by cascading it through the air at a high velocity. Foam reduces combustion by cooling, moistening and excluding oxygen.
Fire lookout tower
A structure located at a high vantage point to house and protect the person performing the duties of a fire lookout.
Fire lookout
A person that keeps an eye for possible fire starts and conditions. They can work in a fire lookout tower or perform the duty as a role for a fire crew on the fireline.
Fire rake
A rake with sharpened teeth instead of blades, for raking a Firebreak.
Fire retardant
Any substance (except plain water) that by chemical or physical actions reduces flammability of fuels or slows their rate of combustion. See retardant slurry, AFFF, and foam for examples.
Fire risk
Fire shelter
An aluminized tent offering protection by means of reflecting radiant heat and providing a volume of breathable air in a fire entrapment situation. Carried as a safety tool, fire shelters are only used in life-threatening situations, as a last resort, as severe burns and asphyxiation often result.
Fire shirt
Distinctive yellow shirts made of Nomex or other lightweight materials of low combustibility, used as uniform PPE of wildland firefighters, and more recently available in other colors.
Fire trail
Australian term for fireroad; a road built specifically for access for fire management purposes.
Fire weather
Weather conditions that affect fire vulnerability, fire behavior and suppression.
Fire whirl
A tornado-like vortex that forms from the stretching of vorticity due to the interaction of air flowing towards and upwards in a fire.
Fire-return interval
Fireline handbook
A small red booklet carried by U.S. firefighters on the firelines, as a quick reference on various firefighting topics.
The part of a control line that is scraped or dug to mineral soil. Also called fire trail. More generally, working a fire is called being on the fireline. May also refer to a wet line, where water has been used to create a burn boundary in light fuels such as grass.
Extreme fire behavior indicated by widespread in-drafts and a tall column of smoke and flame, where added air increases fire intensity, creating runaway fire growth.
A natural or constructed barrier used to stop or check fires that may occur, or to provide a control line from which to work.
Flanks of a fire
The parts of a fire’s spread perimeter that grow to the sides then run roughly parallel to the main direction of spread. Separated flank heads are extremely dangerous in steep terrain.
Any sudden acceleration in rate of spread or intensification of the fire. Unlike blowups, a flare-up is of relatively short duration and does not radically change existing control plans.
Flash fuels
Fuels such as grass, leaves, draped pine needles, fern, tree moss and some kinds of slash, which ignite readily and are consumed rapidly when dry.
Fuel load
The mass of combustible materials available for a fire usually expressed as weight of fuel per unit area (e.g., 20 tons per acre).
Fuel moisture
Percentage of water content of vegetation, an important factor in rate of spread, ranging from dead-fuel and fine-fuel moisture (FFM), of 10 percent or less, to live-fuel moisture (LFM), of 60 percent or more. FFM can be estimated by weighing calibrated wood sticks.
Fuel type
An identifiable association of fuel elements of distinctive species, form, size, arrangement, or other characteristics that will cause a predictable rate of spread or resistance to control under specified weather conditions.
A natural or artificial change in fuel characteristics which affect fire behavior so that fires burning into them can be more readily controlled.


Ground fire
Fire that consumes the organic material beneath the surface litter ground, such as peat fire.


Hand crew
A number of individuals that have been organized and trained and are supervised principally for operational assignments on an incident, typically using hand tools. In the United States, an ordinary hand crew is 20 in number, including supervisors.
Hazard reduction
Precautionary controlled and managed fire lit during cooler and wetter weather in order to reduce the available fuel load. Sometimes incorrectly called a backburn
Head of a fire
The most rapidly spreading portion of a fire’s perimeter, usually to the leeward or up slope; may have multiple heads if there are separated flanking fires.
Heavy fuels
Fuels of large diameter such as snags, logs, large limb wood, which ignite and are consumed more slowly than flash fuels.
A natural or improved takeoff and landing area intended for temporary or occasional helicopter use, typically in remote areas without other access.
A fire crew trained to use helicopters for initial attack, and to support large fires through bucket drops and the movement of personnel, equipment and supplies. Another primary function of helitack is jumper support and retrieval.
Hose pack
A general term covering all types of hose configurations a person would carry to deploy.
Hose Vacuum
A small pneumatic vacuum generator that removes air from the inside of a fire hose making it smaller and firm, it is therefore easier to pack and takes up less space.
Hot spot
A particularly active part of a fire
Hotshot crew
Intensively trained fire crew used primarily in hand line construction, and organized primarily to travel long distances from fire to fire as needed rather than serving only one location.


Incident Command System (ICS)
System first developed to provide a command structure to manage large wildfires in the United States, now widely used by many emergency management agencies.
Incident Qualification Card
Credentials issued to qualified firefighters listing their qualifications and specialties, commonly called a Red Card. These certifications must be renewed annually.
Indian pump
Water vessel carried on one's back, either a rigid can or collapsible bag, with a hose and telescoping squirt pump. Contains five US gallons, and is used on hot spots and during mop-up. Also called a bladder bag (if collapsible), piss pump, or fedco. Of uncertain utility in active crown fires.
Indirect attack
A method of suppression in which the control line is located some considerable distance away from the fire’s active edge. Generally done in the case of a fast-spreading or high-intensity fire and to utilize natural or constructed firebreaks fuel breaks and favorable breaks in the topography. The intervening fuel is usually backfired; but occasionally the main fire is allowed to burn to the line, depending on conditions.
Infrared (IR) detector
A heat detection system used for fire detection, mapping, and hotspot identification.
Initial attack
The actions taken by the first resources to arrive at a wildfire to protect lives and property, and prevent further extension of the fire. Usually done by trained and experienced crews and takes place immediately after size-up.
Interface zone
Where urban firefighting meets wildland firefighting. Structures at the edges of wildlands are threatened and require skills and equipment of both disciplines.
Into the black
Moving from outside the fire front to inside the burned area, which is sometimes the safest place to be in a flare-up.


See Smokejumper


Knock down
To reduce the flame or heat on the more vigorously burning parts of a fire edge, usually by cooling with dirt, water or other retardant.


Firefighter safety mnemonic for lookout, awareness OR anchor point, communications, escape routes, safety zones.
Ladder fuels
Flammable vegetation that helps a ground fire move into the canopy.
Lead plane
Aircraft with pilot used to make trial runs over a target area to check wind, smoke conditions, topography and to lead air tankers to targets and supervise their drops.
Let-burn policy
Administrative decision to defer fire suppression, perhaps because of wilderness and long-term forest conservation considerations.
Light 'em, fight 'em
Derogatory term for wildland crew with a reputation for igniting its prescribed burns carelessly.
Line firing
Activity related to burn out along a fireline, using drip torches, fusees or other flammable materials.
Litter (forest litter)
Surface buildup of leaves and twigs.
Logging slash or logging debris
Tops, stumps, mill ends, limbs left by logging operations. May be beneficial to soil stability, but can dry out and create heavy fuel load hazards.
Helicopter arrangement for lowering external loads (or removing loads) into areas not available for landing, using a long cable suspended from a hard point on the belly of the aircraft.
1.  Safety personnel positioned to monitor the location and behavior of a fire, ready to signal a crew to escape
2.  #Fire lookout tower or fire tower, often on mountain-tops, for viewing the surrounding countryside and watching for signs of fire
3.  #Fire lookout, the person who works in the fire lookout tower
4.  The L of #LCES safety mnemonic


Hand tool used in fireline construction, consisting of a combination rake and hoe.
Extinguishing or removing burning material near control lines, felling snags, and trenching logs to prevent rolling after an area has burned, to make a fire safe, or to reduce residual smoke.
Mutual aid
Cross-jurisdictional assistance with emergency services by pre-arranged agreement.


NFDRS (National Fire Danger Rating System)
Used in the United States to provide a measure of the relative seriousness of burning conditions and threat of fire.
National Fire Protection Association (NFPA)
Fire and safety standards organization; issues various wildfire-oriented standards related to clothing, tactics, equipment, etc.
National Hose (NH)
National Standard Thread (NST) design of threaded couplings used on fire hose in various diameters; incompatible with many types of wildfire hose threads, thus requiring adapters.
National Interagency Fire Center (NIFC)
Coordination facility in Boise, Idaho, operated by several U.S. agencies to provide logistics, weather information and resource coordination for wildfire suppression across the U.S. (formerly BIFC).
National Wildfire Coordinating Group
Coordination agency located in Washington, D.C. which sets national standards for firefighter training and publishes training manuals.
Brand of approved, fire retardant, synthetic, aramid cloth and thread used in personal protective equipment for wildland firefighting, and jumpsuits.


One-hour fuel
Vegetation with large surface-to-mass ratio, a so-called fine fuel (along with 10-hour) that quickly reaches critical (inflammable) moisture levels (fine fuel moisture, FFM) when exposed to heat; compare with 100-hour or 1000-hour fuels (i.e., live fuel moisture, LFM), which take much more heat to ignite.
Personnel assigned to supervisory positions, including incident commander, command staff, general staff, branch directors, supervisors, unit leaders, managers, and staff. Also may be organized according to qualifications and experience, as type I overhead team, and the like. Many positions, functions and interactions of wildfire overhead organizations provided the model for today's incident command systems in the United States.


Palmer drought severity index (PDI)
Technique for measuring impact of soil moisture changes on vegetation, for predicting fire danger and fire behavior.
Parallel attack
Fire containment method where crews construct a fireline at some distance from the edge of the fire (e.g., 100 yards) and then burn out the fuel in the buffer as the fireline is completed.
Perennial grasses
An extremely volatile fuel, after curing, in May, June, and July, which can lead to large, fast fires that may reach larger fuels.
Point of origin
An element of fire behavior, indicating where a fire began, supporting further analysis of where the fire went or will go; evidence of specific origin is often obscured or destroyed by suppression tactics.
Prescribed burn
Deliberately ignited fire for the purpose of forest or prairie management, often to remove heavy fuel buildup or simulate natural cycles of fire in an ecosystem. Also called controlled burns, even if it becomes uncontrollable.
Progressive hose lay
A method of deploying hoses along firelines during suppression and as they are built and reinforced, typically using 1½-inch supply lines, gated wyes and 1-inch lateral lines with nozzles (or spigot valves) every 100 feet or so. As the line progresses, more hoses and valves are added.
Project fire
Any large fire requiring extensive management and the establishment of a temporary infrastructure to support firefighting efforts, such as fire camps.
Combination axe and grub hoe tool with a straight handle, used for building handline. Also known as P-tool


Crew of specialist firefighters who are trained to access a fire area by sliding down ropes suspended from a hovering helicopter. Also used for delivering wilderness first aid if a rapeller is an EMT.
(1) repeat burning of an area over which a fire has previously passed, but left fuel that later ignites when burning conditions are more favorable; (2) an area that has re-burned.
Red card
See Incident Qualification Card.
Red-flag day
Weather conditions creating a critical fire hazard, may require closing the forest to non-emergency activities in order to minimize the risk of accidental wildland fires.


The basic wildland fire training course given to all U.S. firefighters before they can work on the fire lines.
Safety zone
An area cleared of flammable material used for escape in the event the line is outflanked or in case a spot fire causes fuels outside the control line to render the line unsafe. In firing operations, crews progress so as to maintain a safety zone close at hand allowing the fuels inside the control line to be consumed before going ahead. Safety zones may also be constructed as integral parts of fuel breaks; they are greatly enlarged areas which can be used with relative safety by firefighters and their equipment in the event of blowup in the vicinity.
Chainsaw crew, may also include fallers or fellers who are qualified to cut down trees or snags, perhaps while the tree or snag is burning.
Single engine air tanker - small agricultural aircraft converted for use on fires, predominantly during the initial attack phase.
Secondary line
Any fireline constructed at a distance from the fire perimeter concurrently with or after a line already constructed on or near to the perimeter of the fire. Generally constructed as an insurance measure in case the fire escapes control by the primary line.
Initial assessment of fire including fuel load, weather, topography, fire behavior, hazards and exposures of valuable properties. Quickly detects needs for additional resources and sets operational priorities.
Skidder unit
Pre-configured tank, pump, hose for attachment to a logging skidder (large four-wheel-drive tractor with a dozer blade, winch or grapple) to be carried to a fireline.
Debris resulting from such natural events as wind, fire, or snow breakage; or such human activities as road construction, logging, pruning, thinning, or brush cutting. It includes logs, chunks, bark, branches, stumps, and broken under-story trees or brush. See also logging slash
Sling load
Cargo net containing supplies or equipment delivered by longline below a helicopter.
Fire spreading outside the boundaries of a control line.
Humorous pejorative term for those believed to not be doing their share of work.
Slurry bomber
See #airtanker
Colloquial term for a wildland firefighter. Now mostly archaic, except in Minnesota where state department of natural resources firefighters are officially known by that name.
A specifically trained and certified firefighter who travels to remote wildfires by fixed-wing aircraft and parachutes into a jump spot - that may include trees - close to the fire.
A fire burning without flame and barely spreading.
A dead standing tree that can be hazardous.
Spike camp
Remote camp usually near a fireline, and lacking the logistical support that a larger fire camp would have.
Behavior of a fire producing sparks or embers that are carried by the wind and which start new fires (spot fires) beyond the zone of direct ignition by the main fire. A cascade of spot fires can cause a blowup.
Strike team
Specified combinations of the same kind and type of resources, with communications, and a leader.
All the work of extinguishing or confining a fire beginning with its discovery.
Suppression crew (also "Soup Crew")
Two or more firefighters stationed at a strategic location for initial action on fires. Duties are essentially the same as those of individual firefighters; often organized into 20-person crews, including supervisors, for simplified logistics and operations.
Surface fire
Fire that burns loose debris on the surface, which include dead branches, blowdown timber, leaves, and low vegetation, as contrasted with crown fire.


Task force
Any combination of resources assembled for a particular tactical need, with common communications and a leader. A task force may be pre-established and sent to an incident, or formed at an incident.
Not to be confused with crowning, is when a single or small group of trees go up in flames. Torching and group torching are more of a nuisance whereas crown fire is of much greater concern.
Tree jump
A smokejumper can sometimes parachute into a tree canopy if a clearing is not available or suitable.
Turn around
A widened part of a fire break used for turning vehicles around, also used as a safe area during entrapment.
Type I engine
A fire engine designed primarily for fighting fires in structures accessible from roads.
Type II engine
A fire engine designed to carry and pump water for use in fire suppression. Also known as a tender or water tender.
Type III engine
A fire engine designed primarily for fighting wildland fires. These engines are usually able to traverse more rugged terrain than type I and type II engines.


Understory burn
A controlled burn of fuels below the forest canopy, intended to remove fuels from on-coming or potential fires.
Urban interface
The interface zone where man-made structures inter-mingle with wildlands, creating the risk of structural involvement in a wildland fire incident and wildland fire involvement in structure fires, each of which requires different equipment, training, and tactics.


Watch out situations
A list of 18 situations for firefighters to be aware of, which signal potential hazards on the fire line; originated from analysis of generations of similar incidents.
Water tender
Any ground vehicle capable of transporting specified quantities of water.
Wet line
Temporary control line using water or other fire retardant liquid to prevent a low-intensity fire from spreading in surface fuels or to knock down a more intense fire.
Any branch or treetop that is poorly or no longer attached to a tree, but still tangled overhead.
An unplanned, unwanted wildland fire, including unauthorized human-caused fires, escaped wildland fire use events, escaped prescribed fire projects, lightning strikes, downed power lines, and all other wildland fires where the objective is to put the fire out.
An area in which development is essentially nonexistent, except for roads, railroads, power lines, and similar transportation facilities. Structures, if any, are widely scattered.
Wildland fire engine
Fire apparatus specialized for accessing wildland fires with water, equipment and small crew. Size and agility of these units may also be useful for other urban missions.
Wildland fire use fires (WFU fires)
Naturally-ignited wildland Fire that are managed for the purposes of achieving specific previously-defined resource management objectives.[4]
Trees knocked over or broken off by wind, increasing fuel loading and hampers building fireline. Also sometimes called blowdown. Large, unmanaged areas of dense blowdown can create serious fire hazards once the larger fuels become dry.

See also[edit]


  1. ^ Glossary of Firefighting Terms from an Air National Guard website
  2. ^ Glossary of Firefighting Terms 2006 from USDA National Wildfire Coordinating Group
  3. ^ Pausas J.G., Lamont B.B. 2018. Ecology and biogeography in 3D: the case of the Australian Proteaceae Journal of Biogeography,
  4. ^ Fire Use from a U.S. Forest Service website